Drilling system

ABSTRACT

An underwater or underground drilling system comprising a base, a rotatable platform, a pivotable drilling structure and, in certain environments, separate enclosures for housing crew and equipment. The rotatable platform allows drilling in any of a number of directions while the pivotable drilling structure allows drilling to be initiated in a horizontal direction thereby more widely spreading the drilled holes from a single base location and keeping the profile of the system to a minimum thereby preventing collisions with drifting ice or allowing drilling from an underground cavern.

United States Patent Rossfelder et al.

[451 Feb. 18,1975

[ DRILLING SYSTEM [75] Inventors: Andre M. Rossfelder, La .lolla;

William S. Bates, Arcadia, both of Calif.

[73] Assignee: Tetra Tech, Inc., Pasadena, Calif.

' 22 Filed: July 12, 1972 [21] Appl. No.: 271,117

[52] US. Cl 175/5, 61/69, 173/D1G. .2,

[51] Int. Cl E2lb 7/12 [58] Field of Search 175/5-10, 61; 173/43, DIG. .2; 37/56, 64, 65; 61/69 R [56] References Cited UNITED STATES PATENTS 2,331,072 10/1943 Hansen et al. 175/9 2,565,794 8/1951 Young 175/61 2,598,454 5/1952 Smith 173/43 X 2,747,840 5/1956 Miles 175/9 2,783,027 2/1957 Gilbert 175/5 2,783,970 3/1957 Gillespie 175/8 X 2,792,198 5/1957 Braun 175/5 2,937,006 5/1960 Thayer 175/6 2,989,294 6/1961 Coker 175/5 X 3,063,507 11/1962 ONeill et al. 166/.5 X

5/1965 Cobu rn 175/85 3,380,256 4/1968 Rebikoff 175/9 X 3,451,493 6/1969- Storm 175/85 3,516,489 6/1970 Jergins 1 61/69 R X 3,683,521 8/1972 Sloan et al 37/56 3,709,307 l/l973 Clark 175/8 FOREIGN PATENTS OR APPLlCATlONS 994,628 6/1965 Great Britain 37/56 Primary Examinerl-lenry C. Sutherland Assistant ExaminerRichard E. Favreau Attorney, Agent, or Firm-Harris, Kern, Wallen & Tinsley [57] ABSTRACT An underwater or underground drilling system comprising a base, a rotatable platform, a pivotable drilling structure and, in certain environments, separate enclosures for housing crew and equipment. The m tatable platform allows drilling in any of a number of directions while the pivotable drilling structure allows drilling to be initiated in a horizontal direction thereby more widely spreading the drilled holes from a single base location and keeping the profile of the system to a minimum thereby preventing collisions with drifting ice or allowing drilling from an underground cavern.

8 Claims, 7 Drawing Figures 1 DRILLING SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling system, and, more particularly, to a drilling system for an underwater or underground environment where the system may be used during each stage of drilling: exploratory, developmental and production. The system is particularly advantageous in the arctic region where large, floating ice masses would imperil an above surface conventional drilling system.

2. Description of the Prior Art The continuing and ever growing needs for oil and gas are self-evidnet. In order to meet current and anticipate future demands, oil, for example, is being acquired from underground pools which are located under the sea. This type of oil acquisition is commonly referred to as off-shore drilling. It has been estimated that 4,000,000 square miles of the worlds off-shore area in waters less than a thousand feet deep contain potential gas and oil bearing sediments; presently, only about 5 percent of the most favorable of this area is being explored. One of the major problems facing such oil and gas exploitation is the high cost involved with drilling operation and the lack of a system or systems to successfully and economically drill in deep water or areas where weather is inhospitable to a drilling crew.

Various efforts have been made to develop drilling equipment such as exemplified by U.S. Pat. No. 3,451,493 to Storm, U.S. Pat. No. 3,353,364 to Blanding, et al., and U.S. Pat. No. 3,095,048 to ONeill, et al. The storm patent illustrates a drilling system including a tower anchored to the ocean floor and a working area which is located above the surface of the water. Such a system has the disadvantage of exposing the working area to weather conditions which could prove disastrous in ice infested regions and, as was the case to drilling systems in the Gulf of Mexico, when exposed to hurricanes. The Storm patent also illustrates a flexibility in choosing drilling direction. Thus, a wider region could be drilled with the equipment shown then could be drilled with a traditional system which required the drill pipe to enter a hole immediately below the drilling system. Drilling could proceed at a slight angle by deviating the pipe but was still restricted within close limits. Nevertheless, drilling may be accomplished only where guide tubes (designated ll, column 3, line 30 et seq.)

are located so drilling is limited in some finite manner. The second and third mentioned patents illustrate underwater drilling systems which are either remotely operated or are basically enclosed variations of traditional well drilling systems. In an underwater environment such systems have the fatal disadvantage of leaving workmen no escape from such dangers as gas leaks or blow-outs; that is, the life support and drilling areas coincide so that should trouble develop at the drilling location, the drilling crew is trapped. A further disadvantage is that the height of such systems make them potential targets for drifting ice should the systems be used in the Arctic.

As mentioned, arctic drilling includes the special problem of dealing with large, floating ice masses while all drilling operations are plagued with aesthetic and ecology considerations. Further, of course, any drilling mechanism developed must operate in an economical fashion and be suitable for economical manufacture and transportation.

SUMMARY OF THE INVENTION The above-mentioned problems in the prior art are overcome by the present invention which provides in one preferred embodiment a drilling system comprising a base structure for anchoring; a platform connected to the base structure; a plurality of water impermeable enclosures connected to the platform for containing drilling equipment, ancillary equipment and living quarters; the platform being rotatably connected to the base structure; and including means pivotally connected to the platform for directing a mechanism for creating a hole.

It is a general aim of the present invention to provide a drilling system which may be used during each stage of oil and gas acquisition; that is, a system which may be used for exploration, for development and for production.

Another aspect of the present invention'is to provide a drilling system which may be totally submerged underwater or even under the ocean floor so as to be ideal for arctic drilling.

Another object of the present invention is to provide a drilling system which is safe for the operating crew.

Another aim of the present invention is to provide a drilling system which is economical to operate and manufacture, which is aesthetically pleasing and which is ecologically sound.

More particularly, it is an aspect of the present invention to provide a drilling system which divides the human living and work areas from other equipment areas and allows each area to be maintained at different pressure environments.

Yet another aim of the present invention is to provide a drilling system which is able to initiate drilling in any one of an infinite number of directions in a 360 arc from a single anchored location.

A corollary aspect of the present invention is to provide a drilling system which may initiate a drilling hole in a direction which is generally horizontal.

A still further object of the present invention is to provide a drilling system which retains a horizontally disposed upper portion of a drill string in tension while a vertically disposed lower portion of the drill string is in compression.

Another aspect of the present invention is to provide a drilling system which is pivotable and rotatable thereby allowing horizontal drilling, a low profile, and the placement of the system underground.

Other objects and advantages of the invention will appear from the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of one embodiment drilling system illustrating some of the many positions for drilling from a single location.

FIG. 2 is an enlarged front view of the drilling system illustrated in FIG. 1.

FIG. 3 is a side view of the drilling system illustrated in FIG. 2 and including optional above surface equipment.

FIG. 4 is a plan view of the drilling system illustrated in FIG. 2.

FIG. 5 is a sectional view of a tubular structure for directing drill pipes.

FIG. 6 is a sectional view of another embodiment of a tubular structure for directing drill pipes.

FIG. 7 is a perspective view of another embodiment of the drilling system as placed in an underground chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENTS While the present invention is susceptible of various modifications and alternative constructions, illustrative embodiments are shown in the drawings and will herein be described in detail. It should be understood, however, that it is not the intention to limit the invention to the particular forms disclosed; but, on the contrary, the intention is to cover all modifications, equivalents and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring now to FIG. 1, there is illustrated a drilling system 10 including an anchored base 12 to which is rotatably mounted a platform 14. Mounted to the platform is a large drill structure 16 for directing a drill string during drilling operations. A drill string is a mechanism in the form of a length of drill pipes having at its lower end a drilling bit. Also mounted on the platform 14 are three enclosures, a first detachable enclosure 18 for housing a crew living quarter, a second enclosure 20 including a control room and work area, and a third enclosure 22 for housing such equipment as a power plant, steam and heating systems, mud system, etc. The base 12 is generally free flooding and is provided with an air-ballasting mechanism in order to allow sinking, resurfacing, towing or self-propulsion above or underwater.

As illustrated by dotted lines, exploratory drilling may be directed in any number of positions in a circle about the drilling system simply by rotating the platform 14 about the base 12 so as to point the tubular drill structure 16 in a new direction. Once an oil field is confirmed, a multiple number of wells may be drilled from the same location in order to provide for an optimum oil extraction rate. Because of the rotational ability of the drilling system, the plurality of wells may-be widely spaced from one another to achieve an effect similar to spacing a plurality of individual wells. Finally, during the production stage of drilling, the platform, the tubular drill structure and enclosures may be removed from the base and moved elsewhere. The base may remain to act as a production module having production elements 19, with its separators, manifolds and dehydrators for receiving oil from the plurality of wells and then direct the oil to a conduit leading, for example, to onshore storage facilities or to a floating storage facility.

It is an important aspect of the present invention that the drilling system is adaptable to be used during exploratory, developmental and production drilling. Helping to achieve this is the base structure 12, FIGS. 2, 3 and 4, which is shown to have an annular shape including twelve equally spaced openings 30, FIG. 4, to receive pilings 32, FIG. 2, for anchoring the base structure to a portion of the ocean bottom 34. If desirable and physically practical, the base structure may be attached to a pipeline 36, FIG. 2, which in turn connects the base structure and storage facilities on land. As

viewed in FIG. 2, the base structure may also act as a terminus for an underground tunnel 38 from some facility located on shore.

Another important aspect of the present invention is the drilling systems ability to initiate the drilling of a hole in an arc 360 about the location of the base structure. This is achieved by rotatably mounting the platform 14 to the base structure 12 and having rotation take place about a central pivot 40, FIG. 4. The platform may be detachable from the base structure to allow the base structure to be used for production purposes while the drilling mechanism is connected to a new base structure and relocated. Connected to the rotatable platform are the three enclosures 18, 20 and 22 and .the tubular drilling structure 16.

Each'of the enclosures are impermeable to water and provide a major advantage to the drilling system by providing for separation of those regions which are less critical to life support and where equipment may be stored. Thus, should a problem arise due to drilling, there will be some degree of insulation of the crew from the immediate problem area which generally resides 1 around the hole being drilled. The separate enclosures also allow each to exist at different pressures so that, if desired, the primary enclosure used by crew members may be maintained at atmospheric pressure while the infrequently inhabited enclosures may have a pressure ranging anywhere from atmospheric to a much higher ambient pressure.

Referring in particular to FIGS. 2 and 4, the enclosure 18 is detachably mounted to the platform 14 and includes the crews living quarters and life support systems. For example, the enclosure 18 is shaped as a sausage having a living quarter portion 42 and a hyperbaric chamber 44. Passage between portion 42 and chamber 44 is allowed through lock out system 50. Passage between the enclosure 18 and atmospheric pressure portion 58 of the enclosure 20 is accomplished through lock out systems 52, 64 and 54, 66 for personnel at atmospheric pressure. Personnel at a greater pressure in a hyperbaric chamber 56 of the enclosure 20 may be transferred to the chamber 44 through lock out systems 46, 48. The chamber 44 may be used in an emergency in order to undergo decompression. For example, in case of emergency the enclosure 18 can be detached and independently surfaced with crew personnel at either atmospheric or some higher pressure.

The enclosure 20 which is also sausage shaped is, as mentioned, divided into a first high pressure chamber 56 and a second lower pressure portion 58. The chamber 56 includes the lock 48 for access to the enclosure 18 and also includes locks 60 and 62. The lock 60 allows access to the portion 58 of the enclosure, while the lock 62 allows access to the tubular structure 16. The portion 58 includes locks 64 and 66 for access to the enclosure 18 and a lock 68 for access through a passageway 70 to the enclosure 22. In one preferred embodiment, the portion 58 would include a control room, a machine shop and a personal transfer capsule dock as shown in the FIG. 3 embodiment. The chamber 56 comprises a work area, tool storage and an entry way to the tubular structure as already mentioned. The chamber 56 may be used as a dry hyperbaric chamber where the crew may work in a shirt-sleeve environment at any pressure from atmospheric to ambient. Divers may egress through lock 62 and passageway 71 for access to the sea to do such work as repairs and handling.

For example, there may be a need to change a blowout-preventer mechanism. The chamber 56 may be essentially an enclosure for saturated-stage work while the chamber 44 provides for a region in which, through adequate procedure, personnel may be brought back from ambient to atmospheric pressure.

The enclosure 22 is also sausage shaped and includes two decks, a lower deck having a power plant, steam and heating system, sea water distillation unit and the electrical system. A top deck may include a mud system, mud and cement and a chemical storage area. The enclosure 22 includes a lock 72 at the opposite end of the passageway 70 from the lock 68. Other necessary materials to allow drilling such as lubricating oil and other chemicals may be stored elsewhere along the platform. For example, a chemical tank 76, a lubricating oil storage container 78, a clean water tank 80 and a portable water storage tank 82 may be disposed at various locations about the platform.

Positioned between the enclosure 22 and the tubular drilling structure 16 is a crane 84, FIG. 4, which may be used to load the drill structure with drill pipe from a pipe storage platform 88 mounted to the enclosure 20. A second crane 90, FIG. 2, may be used to assist in movement of drill pipes to the drill structure. In addition to the enclosures containing the various equipment and housing necessary to operate a drilling system, the enclosures may also include tanks for ballast as shown at the top and bottom of each enclosure, i.e., ballast 87 and 89 of the enclosure 18.

As mentioned, each of the enclosures may be maintained at different pressure levels, depending upon the proposed occupancy of the enclosure. For example, the living quarters portion 42 of the enclosure 18 may be maintained at one atmosphere as may the control room portion 58 of the enclosure 20. The chamber 44 of the enclosure 18 and the chamber 56 of the enclosure 20 may be maintained at a greater pressure as may the enclosure 22 since each of these regions are not intended for constant human occupancy and any member of the crew moving through this area temporarily may do so with proper protective equipment and under proper control procedure. Pumps 51 located within the enclosures 18, 20, and 22 provide for and allow the controlling of the desired pressures within the enclosures.

Another important aspect of the present invention is to provide a drilling system which is ideal for Arctic drilling because the profile of the system is sufficiently compact so that when placed on or below the ocean floor, there is little likelihood of an impact occurring with a floating ice mass. As mentioned hereinabove, prior art systems required at least 60 feet in height to handle the usual pipe lengths since drilling proceeded in a traditional vertical direction. With horizontal drilling this problem is obviated. Horizontal drilling underwater drilling also obviates all sea/air interface problems such as damage caused by wave action or ships. The ability to initiate drilling in an almost horizontal direction is a major advantage herein. The upper portion of the drill string is maintained in tension while the lower portion is maintained in compression. This is achieved by the unique tubular passageway 71 so as to subtend an arc, FIG. 3, from a near vertical position shown in dotted line to a more nearly horizontal position shown in solid line. For example, when the tubular drilling structure is located in its nearly vertical position, it may be used to sink the pilings 32 to anchor the base structure 12. When the tubular structure, however, is more horizontally disposed, a drill string 100, FIG. 3, may be initiated in the nearly horizontal position and allowed to assume a more traditional vertical position as the drill string proceeds away from the drilling'system. This is shown in an exaggerated form in FIG. 3 where an upper portion 102 of the drill string 100 is shown as well as a bottom portion 104.

Itis apparent that initiating a well in the above described fashion would allow a far larger region to be drilled from a single base location than would the conventional method in which a drill string is initially in a vertical direction with slant drilling being accomplished within very limited ranges. It is noted that as the bit of a traditional deviated drill string approaches a horizontal position, the drill bit will no longer be in compressionas the weight of the drill string will no longer be loaded on the bit, but instead will be carried by the wall of the drilled hole. The present invention obviates this problem by drilling in a generally horizontal direction initially where the weight of the drill string is not substantial under either the traditional method or the present method and has a negligible effect on the ability to drill. However, as the drilling continues, the drill string assumes a more vertical position at which point the weight of the drill string then bears directly upon the drill bit and facilitates drilling. This advantage is in addition to the substantially greater spread achieved between well holes using the method of the present invention as compared to traditional drilling methods.

Referring to FIG. 2 again, a wellhead or Xmas tree 121 is illustrated over a fully drilled hole. A Xmas tree is a production manifold placed upon the drilled hole and includes the necessary valves to allow the connection of oil carrying conduits and the transport of the oil to a distant point like an on-shore facility for example. The tubular structure 16 is shown after rotation in another position for drilling another hole.

Referring to FIGS. 5 and 6, two cross-section configurations of drill structures are illustrated, wherein FIG. 5 the tubular structure 16a is illustrated having drill pipe located circumferentially about the inner wall and directed to a central position for insertion into the ground. The embodiment 16b shown in FIG. 6 illustrates an elongated recessed portion into which the drill pipes are positioned before being directed into the ground.

In one variation of the system, a submersible l 12 may be docked alongside the enclosure 18 and be used to transport crew members and supplied between the waters surface and the drilling system. Another variation illustrated in FIG. 3 shows a surface unit 114 providing guide lines 116 and 118 between the surface unit and the drilling system to enable a personnel transfer capsule 120 to be used to transport crew members and supplies. Additionally, an air supply line 122 may be installed between the surface unit 114 and the drilling system. Further, the surface unit may have an area to allow the landing of a helicopter 124 as illustrated. It is to be understood that such a surface unit may be used only where ice conditions permit. Where ice conditions do not permit, the drilling system will be totally submerged and self-contained.

Referring now to FIG. 7, there is illustrated a modifled version of a drilling system having a base 142 anchored into the ground and a rotatable platform 144 mounted atop the base. Pivotably mounted atop the platform is a structure 146 for directing a drill string into the ground. The system 140 is different from those described hereinabove in that it is designed for operation underground at atmospheric pressure so that the enclosures are not needed. As illustrated, the system is located in an underground Chamber 148 located at the end of a tunnel 150 which opens at the ground surface 151, i.e., the ground/air interface. In addition, the chamber is also shown located under an ocean floor 152 though it is to be understood that drilling can take place in an underground cavern without being in the vicinity of an ocean or other body of water.

When located under the ocean floor, a shaft 154 may be formed vertically between the underground chamber and the ocean floor for the purpose of relieving excess pressure such as occurring during a blow out. Partitions such as large check valves 156 and 158 may be placed at each end of the shaft to allow passage in a direction away from the chamber but not toward the chamber. When located underground, but not under an ocean floor, a shaft may be formed leading to the ground surface from the chamber to provide for this same pressure relief function as described. A lock out passage 161 is provided within the tunnel as a safety device in case of blow out, fire or flooding.

The low profile of the system allows the tunnel and the chamber or cave to be formed in a single geological strata which if competent will provide a strong enclosure in which to carry on drilling operation.

Referring to FIG. 7 again, the platform 144 supports racks 160 for storing drilling pipe and sub-platforms (not shown) from which a crew may operate the system. Underground drilling is ideal for those regions where the surface environment is hostile such as at the Arctic or where ecological consideration can best be served by going underground.

In order to allow for relatively low power consump- I tion for pivoting the large tubular drill structure when submerged, the interior of the tubular structure may be filled with compressed air thereby creating a buoyant effect. A rotatable hinge cover 171 is provided at the lower end of the drill structure for moving the blow out preventer from the well head work area. A blow out preventer is a giant check valve, which must be changed when the diameter of the drill string is changed.

Another modification of the system is to include a turbo drilling mechanism. Thus, instead of rotating the entire drill string during drilling, the bit, only, is rotated by a fluid such as drilling mud.

The drilling systems described are economical to manufacture as well as reasonably economical in operation so as feasible prospect than ever before. In addition, the present drilling systems are aesthetically more pleasing in that, for the most part, they are totally submerged underwater and may even be partially covered by the ocean floor or hidden underground. Further, by placing the drilling system immediately adjacent the well hole, ecological disasters such as blow outs may be better controlled thereby disturbing to a minimum the natural balances in the immediate vicinity of the system.

We claim:

1. A drilling system for functioning in a subsurface environment comprising:

a base for being connected to ground;

a platform rotatably connected to said base;

a cylindrical drilling structure pivotally mounted to said platform, said drilling structure including a hinged cover over one end thereof; and

a plurality of drill pipe aligned parallel to the longitudinal axis of said drill structure and along the inner periphery thereof.

2. A drilling system for functioning in an underwater environment comprising:

a base for being connected to ground;

a platform removably and rotatably connected to said base;

a drill structure pivotally mounted to said platform to allow drilling in a generally horizontal direction;

a plurality of enclosures mounted to said platform in communication with said drill structure and laterally spaced therefrom; and

means connected to said enclosures for providing and controlling pressure therein,

said plurality of enclosures includes three enclosures,

two of said enclosures having first chambers at atmospheric pressure and second chambers having a variable pressure and the third enclosure having a chamber at ambient pressure.

3. A drilling system as claimed in claim 2 including means for selectively communicating the chambers of said two enclosures; and

means .forselectively communicating the chambers of one of said two enclosures and the chamber of said third enclosure.

4. A drilling system for functioning in an underwater environment comprising:

a base for being connected to ground;

a platform removably and rotatably connected to said base;

a drill structure pivotally mounted to said platform to allow drilling in a generally horizontal direction;

a plurality of enclosures mounted to said platform in communication with said drill structure and laterally spaced therefrom; and

means connected to said enclosure for providing and controlling pressure therein wherein at least one of said enclosures has a first chamber at atmospheric pressure and a second chamber has a variable pressure, and wherein said one enclosure is detachable from said platform.

5. A drilling system for functioning in an underwater environment commprising:

a base for being connected to ground;

a platform removably and rotatably connected to said base;

a drill structure pivotally mounted to said platform to allow drilling in a generally horizontal direction;

a plurality of enclosures mounted to said platform in communication with said drill structure and laterally spaced therefrom;

means connected to said enclosure for providing and controlling pressure therein wherein one of said enclosures has a first chamber at atmospheric pressure and a second chamber has a variable pressure; and

means for selectively communicating the interior of said drill structure with said enclosures.

6. A drill structure for functioning in an underwater environment comprising:

abase for being connected to ground;

said base being selectively floodable and including production elements therein;

a platform removably and rotatably connected to said base;

a drill structure pivotally mounted to said platform to allow drilling in a generally horizontal direction;

a plurality of enclosures mounted to said platform in communication with said drill structure and laterally spaced therefrom; and

means connected to said enclosures for providing and controlling pressure therein wherein at least one of said enclosures has a first chamber at atmospheric pressure and a second chamber has a variable pressure.

7. A drilling system for functioning in a subsurface environment comprising:

a drilling chamber;

a tunnel connecting said drilling chamber with the ground surface;

a drilling device for allowing drilling in a generally horizontal direction including a base for anchoring, a platform rotatably connected to said base and a drill structure pivotally mounted to said platform;

an opening positioned above said drilling device and extending upwardly therefrom for allowing the escape of high pressure from said drilling chamber; and

means located in said tunnel for blocking the release of high pressure in said drilling chamber.

8. A drilling system as claimed in claim 7 including pressure responsive valve means positioned within said opening for releasing pressure only when the pressure on one side of the valve means within the drilling chamber is greater than the pressure on the opposite side of said valve means. 

1. A drilling system for functioning in a subsurface environment comprising: a base for being connected to ground; a platform rotatably connected to said base; a cylindrical drilling structure pivotally mounted to said platform, said drilling structure including a hinged cover over one end thereof; and a plurality of drill pipe aligned parallel to the longitudinal axis of said drill structure and along the inner periphery thereof.
 2. A drilling system for functioning in an underwater environment comprising: a base for being connected to ground; a platform removably and rotatably connected to said base; a drill structure pivotally mounted to said platform to allow drilling in a generally horizontal direction; a plurality of enclosures mounted to said platform in communication with said drill structure and laterally spaced therefrom; and means connected to said enclosures for providing and controlling pressure therein, said plurality of enclosures includes three enclosures, two of said enclosures having first chambers at atmospheric pressure and second chambers having a variable pressure and the third enclosure having a chamber at ambient pressure.
 3. A drilling system as claimed in claim 2 including means for selectively communicating the chambers of said two enclosures; and means for selectively communicating the chambers of one of said two enclosures and the chamber of said third enclosure.
 4. A drilling system for functioning in an underwater environment comprising: a base for being connected to ground; a platform removably and rotatably connected to said base; a drill structure pivotally mounted to said platform to allow drilling in a generally horizontal direction; a plurality of enclosures mounted to said platform in communication with said drill structure and laterally spaced therefrom; and means connected to said enclosure for providing and controlling pressure therein wherein at least one of said enclosures has a first chamber at atmospheric pressure and a second chamber has a variable pressure, and wherein said one enclosure is detachable from said platform.
 5. A drilling system for functioning in an underwater environment commprising: a base for being connected to ground; a platform removably and rotatably connected to said base; a drill structure pivotally mounted to said platform to allow drilling in a generally horizontal direction; a plurality of enclOsures mounted to said platform in communication with said drill structure and laterally spaced therefrom; means connected to said enclosure for providing and controlling pressure therein wherein one of said enclosures has a first chamber at atmospheric pressure and a second chamber has a variable pressure; and means for selectively communicating the interior of said drill structure with said enclosures.
 6. A drill structure for functioning in an underwater environment comprising: a base for being connected to ground; said base being selectively floodable and including production elements therein; a platform removably and rotatably connected to said base; a drill structure pivotally mounted to said platform to allow drilling in a generally horizontal direction; a plurality of enclosures mounted to said platform in communication with said drill structure and laterally spaced therefrom; and means connected to said enclosures for providing and controlling pressure therein wherein at least one of said enclosures has a first chamber at atmospheric pressure and a second chamber has a variable pressure.
 7. A drilling system for functioning in a subsurface environment comprising: a drilling chamber; a tunnel connecting said drilling chamber with the ground surface; a drilling device for allowing drilling in a generally horizontal direction including a base for anchoring, a platform rotatably connected to said base and a drill structure pivotally mounted to said platform; an opening positioned above said drilling device and extending upwardly therefrom for allowing the escape of high pressure from said drilling chamber; and means located in said tunnel for blocking the release of high pressure in said drilling chamber.
 8. A drilling system as claimed in claim 7 including pressure responsive valve means positioned within said opening for releasing pressure only when the pressure on one side of the valve means within the drilling chamber is greater than the pressure on the opposite side of said valve means. 